It is not a standard metric in an email performance report, but you can pull in the "First Activity" and "Last Activity" standard columns, "First Activity" being the date of first engagement with the email.

I would start by asking what you're looking to do with that information?

Couple thoughts here without the actual use case:

1) Are you also using SFDC? Automating completed activities for "email sent / delivered" for the lead/contact is fairly easy to do as a part of your other workflows in a smart campaign. You can then pull an activity report in SFDC which by default will have the date and time for that activity. Be cautious though. Syncing everything can slow down your systems or max out your API calls.

2) Alternatively, you can look at the results of your Send Smart Campaigns already performing other tasks for that send program, like updating the Program Status to Delivered or Opened. Downloading the results, playing with the data a bit and/or using a quick pivot table will allow you to see the time and date stamp of each activity for each lead. The time logged is going to be the time at which they completed that flow step, not when it was triggered, so depending on how many flow steps and any wait steps might be delayed by a minute, but it's going to get you very close.

You could also look at using nested Send Programs for your outbound communications. This would give you visuals and automatic engagement scores. Additionally, it breaks out the open times into groups. You'd still have to synthesize that data outside of Marketo to compare days of the week, but it would show you spikes in opens related to time of day. I also recommend playing with A/B testing on your emails for more subject line data.

Hi, Dan, yes that was something I was looking to do. I have to admit I've inherited Marketo from a predecessor, and she was never able to figure out how to make the revenue cycles work properly. Is there a way to create this report without having our revenue cycles set up?

Sure, the Email Analysis report is not dependent on having your Revenue Model defined. All that's required is that you've purchased the Revenue Cycle Explorer (now called "Advanced Analytics") add-on from Marketo.